fix: add SSH backend to terminal requirements check

The SSH backend was missing from check_terminal_requirements(), causing
it to fall through to `return False`. This silently disabled both the
terminal and file tools when TERMINAL_ENV=ssh was configured.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tools/terminal_tool.py

@@ -1068,6 +1068,10 @@ def check_terminal_requirements() -> bool:
                 result = subprocess.run([executable, "--version"], capture_output=True, timeout=5)
                 return result.returncode == 0
             return False
+        elif env_type == "ssh":
+            from tools.environments.ssh import SSHEnvironment
+            # Check that host and user are configured
+            return bool(config.get("ssh_host")) and bool(config.get("ssh_user"))
         elif env_type == "modal":
             from minisweagent.environments.extra.swerex_modal import SwerexModalEnvironment
             # Check for modal token